Recovering sucrose from mixtures containing reducing sugars



Patented @ctQ, 192s.

HENRY QDAHLBER QQF DENVER, Geronimo.

. nncovnnnve' sucnosn FROM ivrrxrunns CONTAINING REDUCING snenns;

No Drawing.

This; invention relates to a process for recovering sucrose from m xtures of sucrose and reducing sugars, and pertains particularly to steps by which such sucrose content maybe obtained more readily and more cheaply than has heretofore beenpossible.

y 1 In this'present invention, it has been found that the presence of reducing sugars-exercises an undesirable dissolving effect on saccharates and which effect causes resultant loss in sucrose production. This can belargely prevented by procedure hereinafterdescribed and in accordance with which the amount of sucrose compared to the amount of'reducing sugar in the mixture about to undergo treatment is regulated; 1

Many attempts have been madeto recover sucrose from syrups containing both sucrose and reducing sugars. Atypical example of such syrup is cane molasses which possesses various materials in proportions which varyaccordingto theoutput of'the factory. A. typical analysis of a typical example of cane molasses is: Y e

. i Percent.

5 Dry substance 1 81. 8 Polarization 27. 5 Sucrose Q "31.' 7 Reducing suga-rs 21.0

Although the composition ofsyrups, containing sucrose andireducingsugars, may vary within rather-wide limits,the majority of them are characterized by having a ratio of sucrose to reducing sugar of from 1.1 to '1"to 2.5 to 1. 'The presence'of reducing sugars in these syrupshas always been a seri-' Y ous obstacle in the way of precipitating the sucrose with an alkaline earth. In thec'ase or barium saccharates.

V or .1. There has been incomplete precipitati of sucrose, I r

sugars I v .calciujm saccharate.

reducingsugars are initially. destroyed by "purity of-saccharate isobtained, probably. .only about 80 per-centfpure. The, second Ash 10:4:

of molasses from sugar beets, containing no reducing sugars, it has been possible for many years to recover sucrose as calcium, strontium Treatment-of cane products, however, hasmet with failure par 7 complete precipitationof sucrose. Thisill bec-lear in the follow ng comparison in Wh ch: I twosyrups wlth difierent ratlos of sucrose to a ticularly'when it has been attemptedtovpre V a p y reducing sugars aregtrleated, 1n. exactlythe 1 cipitate in a single step onezof thsesaccha rates. and probably for the following reasons has been formation of "highly Dry substance wmsss 7 Application filed. Septeri1ber23, 1926. Serial No. 137,379,

3. Saccharates of low purity have been Q formed. I 1- Various methods have been proposedto overcome. the difiiculties thus experienced.

One method employs fermentation of the. re,-

ducmg sugars by the use'o-f microorganisms 0f. the pseudo-saccharomyces apiculatus group before precipitating the sucrose j'as By another method the prolonged heating at 85,C.-with mono-barium silicate, afterwhich thesucrose is precipitated as a. saccharate. Both offlthese inclicated methods are difficult to perform and costlyto operate and the reducing sugars are V not completely removed.

I The first 'method i has proved, unsatisfactory because all e of ,the

reducing sugars are not'fermented and a low method is objectionable because. the prolonged heatmg ata C.. ca-usesdecomposition of both. sucrose and reducing sugars purity of the bariumsaccharate.- Both of these methods involve the use-of several steps for the production of the saccharate auditsprecipitation. t In contrast to knownprocesses and in contrast to thefabove identified processes the present improvement is very simple and gives relatively high yields of extractable sucrose. The new process is performed outrightin a direct single step of barium saccharate precipitation, and-"is particularly adaptedto I treatment of'cane syrups for'the precipitation of sucrosewitli the use of barium hydrate.

As, a result of the present invention iti'has' nowbeen established that barium, saccharate is apparently quite soluble in a solution ofreducing sugars,and the' pres'encef of the latter in largequantities therefore causes very insame wayfwithi? 5 per cent 13210 on weight'of p 1. I Direct polarizationliiw rass 455- 75 which products afi'ectboth the color and the to reducing sugars in syrup No. 2 causedyery incomplete precipitation, only 65.4 per cent. This result is typical. The precipitate n syrup No. 2 proved to-be very fine gralned and'for ned' with great difliculty whereas the precipitateinillo. l Was crystalline, extremely so, and easy to filter. V i

"Thep'resent invention. iszdlrected toward thepreventingof theso'lubility effect of the reducing sugars on barium saccharate. This is done by artificially regulating the ratio of sucrose to reducing sugars.

This regul ation maybe 'GiiflBCtQd by either of the two following'methods:

' 'By increasing the ratio of sucrose to ii'educin'gsiigars toa minimum 0152.8 to "130, respectively, andbeyond this minimum to any desired maximum by mixing beet molasses containing no reducing sugars With cane molasses conta ning a ratio lower than 2.8

b. By i'ncreasing the ratio of 'su'croseto reducing sugars to a minimum of, 2.8t-o 1.0,

respectively, and beyond this minimum to any desired maxi nii'nrby mixing two cane syrups, one with aloWer ratio than 2.8 toll) and the :other with a ratio higher than 2.8

By means ofthe': above prescribedregulation of theJsucrose-rediicing sugar ratio, it

becomes n'oss'ible' to obtain maximumreci 3i- 1 i :7 I I tation of sucrose, and with resultant high purity saccharate juices, Using this 'procedure saccharate juices havebeenobtained having purities, atter carbonation, as'high as 93.0 percent, K116113218 Without such regulation purities fell as low 750 per cent. It

is lrnownthat the yield of extractable sugar rises 'very rapidly withsmallincreases in cent ii extractablesugar. c p The essential stepsof the complete process purity, for example 1. per; cent increase in purity. eflecting an' ncrease oliabout 2.5

may-be summarized as follows:

1, Regulating the'ratioas describedabove. 2. Precipit'ating the sucrose with barium hydrate at a temperature of from 60 C(to V r 3. Recovering sucrose from the barium saccharate-by well known methods;

The second and third steps are necessarily mother liquor,

finery also produces [intermediate syrups known as concentrated sweet- Water and which are obtained by Washingthe usual bone char filters'. "Concentrated sweetwater"syrup is hi ghiiisu crose an dlow i n reducing sugar and '7 Reducing sugars 11.0 predicated on the regulation of sucrose to Ratio sucrose to red. sugaiu; 4.1t0 1 reducing sugar so that ite'xceeds'2;8fto 1.0. BaO used on sucrose 75% 'Such regulation is the step. that Snakes the of sucrose precip'itated 94.6% process commercially operable and ad-.

y N0 2 V Vantageous, inasmuch as without it-the conv f SUITIPUOII Of barium reagent is too high, the iP 8- loss of sugar in the mother liquor is too great y SubStiLIlCe -ri and theresultant purity of the saccharate Reducing sugars. 15.9 j i j t l Ratio Sucrose Sugar 24130 1 The process can be readily adapted to the B210 u 011 3 5 a present process o-f cane sugar refining in the Q S Preclplmted following way: A cane sugar refinery pr'o- It is ObviotisflOm the comparison of these "(111C975 j -y molasses having two sets of data that thelow ratio of sucrose ducing "Sugar t, quite unsuitable barium saccharate precipitation; Such are is thereforefverysuitable for use in increasing the'i'atio of sucrose to reducing sugars in the final molasses. At present, no 'siigar is *being'lecovered fromthe final molasses and only a small part of the-available sugar is recovered from the concentrated sweet Water.-

By combining thetwo syrups in proper proportions to get a ratiOofnioi-e than 2.8 to 1.0 a'totalsucrose recovery of 751361 cent to 85 per cent may be effected. If concentrated sweet'watersyrup isnot readily availab'leythe same result can be obtained by. artificially changing the ratio in the final'refin ery molasses by adding to it beet molassesiinthe devsired proportions. i V H Althoughbarium saccharate is preferred it Will be obvious that calcium and strontium s'accli'aiiates niaybeproduced even though not so effectively or so much desired;

Emphasisis to'be placed on the 'tact that with the use 'ofbarium hydroxidethe addition of this material and the precipitatiouis etfected directlyandin a'singlestep;

It is noteworthythat the use oi. mass action is invoked in forming a precipitate of'ba-rium saccharate from syrups 1 containing reducing sugarss'and the precipitate is formed under such conditions that it. is of a crystalline'na tiire andthere'itore occludes aminimum of the llo The efi'ec'toftheladjiistment of the 'concentration of sucrose :and reducing sugars in a Syl'llp:wltll relation to eachother actuallyresuits in' a minimum of solvent-action on a precipitateiof bariiiinsaccharatewhenbarium v --hydroxide is added toztlieisyrup at a hightemperature.

1; The processof recovering sucrose-front mixtures of sucrose .andfredu cing sugars of sucrose and reducing sugars by regulating the ratio of amount'of sucrose. to reducing sugar to include atleast 2.8 of sucrose to 1.0 of reducing sugar, preclpltatmg the sucrose b treatin the mixture thus re ulated with a n a a: alkallne earth metal and under, temperature conditions of between 60 C. and 85 0., and separating the saccharate into an alkaline earth metal compound and sugar syrup.

3. The process of recovering sucrose'from mixtures of sucrose and reducing sugars which process consists of treating a mixture of sucrose and reducing sugars by regulating the ratio of amount of sucrose to reducing sugar to include atleast 2.8 of sucrose to 1.0 of reducing sugar, precipitating the sucrose by treating the mixture thus regulated with barium hydrate, and separating the resultant barium saccharate into a barium compound and a sugar syrup. 4. In the manufacture of sugar from mixtures of sucrose and reducing sugars, the step of preparing the mixture for treatment with an alkaline earth metalwhich step con- I sists of regulating the ratio of the amount of sucrose to reducing sugar to include at least 2.8 of sucrose to 1.0 of reducing sugar.

5. In the manufacture of sugar from mixtreating a mixture including sucrose and re ducing sugars by regulating the ratio of amount of sucrose to reducing sugar toinclude at least 2.8 of sucrose to 1.0 of reducing sugar, and precipitating the sucrose by treating the mixture thus regulated directly and in a single step with barium hydrate and thus forming barium saccharate.

6. In the manufacture of sugar from mixtures of sucrosev and reducing sugars, the step of forming an alkaline earth metal saccharateeitrom a mixture including at least 2.8 of sucrose to 1.0 of reducing sugar, which step consists of adding to such a mixture directly in a single step the requisite amount of barium hydroxide to combine with the sucrose and thereby forming barium saccharate.

7. The process of recovering sucrose from mixtures of sucrose and reducing sugars,

'ture.

which process consists of regulating the ratio 8 of amounts of sucrose to reducing sugar in final cane refinerymolasses and'until the. ra-

tio of sucrose to'reducing sugar is respectively 2.8 to 1.0 by adding to such final molasses the concentrated sweet water obtained by washingfilters and which sweet water is higher'in content of sucrose than is the content of sucrose in molasses.

8. In the process of recovering sucrose from mixtures of sucrose and reducing sugar, the

step of regulating'the amount of sucrose to the mixture contains at least 2.8' of sucrose to 1.0 of reducing sugar. 9. In the manufacture of sugar from mixtures of sucrose and reducing sugars, the

steps of preparing a mixture containing suarose and reducing sugars fortreatment with an alkaline earth metal hydroxide to coun' teract thedissolving action of the reducing sugar on the saccharate byincreasing the amount of sucrose compared to the amount of reducing sugar by addmg a sucrose cone taining material to the mixture, and thereafter treating the mixture so prepared with an alkaline earth metal hydroxide and thereby producing a saccharate.

10. In themanutacture of sugar'from mixtures of sucrose and reducing sugars, the steps of preparing a mixture containing sucrose and reducing sugars for treatment with an alkaline earth metal hydroxide to counteract the dissolving action of the reducing sugar on the saccharate'by increasingthe amount of sucrose in the mixturewith' re spect to the amount of reducing sugar pres.-.

ent, and thereafter treating themixture so prepared with an alkaline earth metal hy droxide and thereby producing a saccharate.

11. In the manufacture'of sugar'from mix tures ofsucrose and reducing. sugars, the steps of preparing a mixture containing sucrose and reduclng sugars for treatment Vw1th' adding sucrose to themixtureuntil themixture displays substantially no dissolvingactionon an alkaline earth metal saccha'rate when the latter'isprecipitated from the mix- In testimony whereofI aifix-my signature.

HENRYW. DAHLBERG; I 

